Low-cost improved coupled-inductor delta source dc-dc boost converter and control method

Abstract

This invention discloses a low-cost improved coupled inductor Delta source DC-DC boost converter and its control method, belonging to the technical field of power electronic converters. It includes a DC voltage source. V in ,diode D 1. Diode D 2. Capacitor C 1. Capacitor C 2. Capacitor C 3. Load resistance R Power switching devices S 0 and the coupled inductor; the coupled inductor includes three windings and the winding current of the coupled inductor. i N1 The three windings are respectively windings N 1. Winding N 2 and winding N 3; The DC voltage source V in The positive terminals are respectively connected to the diode. D 1. Positive terminal, capacitor C 1. Cathode electrical connection; the diode D The cathodes of 1 are respectively connected to the coupled inductor windings N 1's positive terminal and coupled inductor winding N 2. Cathode electrical connection. This invention breaks through the bottleneck of traditional Boost converters being limited by series impedance and voltage gain improvement under high duty cycle. It achieves a boost ratio much higher than traditional solutions within a reasonable duty cycle range, effectively adapting to the power conversion needs of low-voltage input and high-voltage output, such as photovoltaic power generation.

Description

Technical Field

[0001] This invention relates to the field of power electronic converter technology, specifically to a low-cost improved coupled inductor Delta source DC-DC boost converter and its control method. Background Technology

[0002] In photovoltaic power generation systems, the output voltage of photovoltaic modules is usually low and fluctuates widely. In order to meet the high-voltage power supply requirements of subsequent grid-connected power generation or energy storage systems, high-gain DC-DC boost converters have become an indispensable core power conversion unit in this field. Their performance directly determines the energy conversion efficiency and operational stability of photovoltaic power generation systems.

[0003] Traditional Boost DC-DC converters, as the most basic boost topology, theoretically have a voltage gain determined by the duty cycle. Theoretically, a high boost ratio can be achieved when the duty cycle approaches 1. However, in practical engineering applications, due to non-ideal factors such as the on-resistance of the switching transistors, the series resistance of the inductors, and parasitic impedance in the circuit, the voltage loss caused by the series impedance increases sharply with the increase of the duty cycle. This results in the actual output voltage gain not increasing synchronously with the duty cycle, severely limiting the boost capability and making it difficult to meet the high-gain power conversion requirements of photovoltaic power generation systems with low-voltage input and high-voltage output, significantly restricting its application scope.

[0004] To overcome the gain bottleneck of traditional Boost converters and achieve high-gain DC power conversion, Delta-source DC-DC boost converters have been gradually proposed and applied. However, due to inherent defects in their topology, this type of converter suffers from discontinuous input current, which not only generates significant input current ripple, increasing the impact on upstream photovoltaic modules, but also increases the difficulty and cost of electromagnetic interference (EMI) filtering. Simultaneously, its duty cycle range is strictly limited; extreme duty cycle conditions can easily lead to a surge in switching losses and excessive device stress, thereby increasing overall system losses and hardware costs, affecting the long-term stable operation of the converter, and making it difficult to meet the high-efficiency and reliable application requirements of photovoltaic power generation systems. Summary of the Invention

[0005] The purpose of this invention is to provide a prefabricated box-type building space construction method based on container space, so as to solve the above-mentioned shortcomings in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a low-cost improved coupled inductor Delta source DC-DC boost converter, comprising a DC voltage source. V in ,diode D 1. Diode D 2. Capacitor C 1. Capacitor C 2. CapacitorC 3. Load resistance R Power switching devices S 0 and the coupled inductor; the coupled inductor includes three windings and the winding current of the coupled inductor. i N1 The three windings are respectively windings N 1. Winding N 2 and winding N 3; The DC voltage source V in The positive terminals are respectively connected to the diode. D 1. Positive terminal, capacitor C 1. Cathode electrical connection; the diode D The cathodes of 1 are respectively connected to the coupled inductor windings N 1's positive terminal and coupled inductor winding N 2. Cathode electrical connection; the capacitor C The positive terminal of 1 is connected to the capacitor. C 2's positive terminal and coupled inductor winding N 2's positive terminal and coupled inductor winding N 3. Positive electrical connection; the coupled inductor winding N The cathodes of 1 are respectively connected to the coupled inductor windings N 3 Cathode, power switching devices S 0 drain, diode D 2 is electrically connected to the positive terminal; the diode D The cathodes of 2 are respectively connected to the output voltage regulator capacitor. C 3's positive terminal, load resistor R One end is electrically connected; the DC voltage source V in The cathodes are respectively connected to the capacitor C 2 Cathode, power switching device S 0 source, output voltage regulator capacitor C 3 Cathode, Load Resistor R The other end is electrically connected.

[0007] Preferably, the converter can achieve high voltage gain, common ground for input and output, and continuous input current.

[0008] Preferably, the power switching device S 0 represents a MOSFET switch, whose gate is used to receive a drive signal to enable the switch to turn on and off.

[0009] Preferably, the three windings of the coupled inductor N 1. N 2. N 3. Adopts a common core structure, winding N 1 and windingN 2. Winding N Mutual inductance coupling exists between the three components, which is used to increase voltage gain and suppress current ripple.

[0010] Preferably, the capacitor C 1 and capacitor C 2 are voltage divider capacitors. The capacitance values ​​of the two capacitors are equal. They are used to divide the input voltage, reduce the voltage withstand requirements of the device, and reduce the overall cost.

[0011] Preferably, the diode D 1 and diode D Both are Schottky diodes, which have the characteristics of low forward voltage drop and fast switching speed, and are used to reduce the conduction loss of the converter.

[0012] Preferably, the output voltage regulator capacitor C 3 is an electrolytic capacitor used to stabilize the output voltage, suppress output voltage ripple, and ensure stable voltage across the load.

[0013] Preferably, the winding of the coupled inductor N 1. N 2. N The turns ratio of 3 can be adjusted according to the actual voltage gain requirements, and the adjustment range of the turns ratio is from 1:1:1 to 1:3:3.

[0014] Preferably, the power switching device S The duty cycle of 0 is adjustable from 0.1 to 0.8, and the output voltage can be continuously adjusted by adjusting the duty cycle.

[0015] Preferably, the input voltage range of the converter is 12V-48V, and the output voltage range is 50V-200V, which is suitable for application scenarios with medium and low voltage input and medium and high voltage output.

[0016] A low-cost control method for an improved coupled-inductor Delta-source DC-DC boost converter is disclosed. This method, applied to the aforementioned low-cost improved coupled-inductor Delta-source DC-DC boost converter, includes two switching modes: a first switching mode and a second switching mode, described in detail below. S1, First switching mode: Power switching transistor S 0 conduction, capacitor C 2. Through power switching devices S 0 for coupled inductor winding N 1. During charging, due to the principle of magnetic induction, the coupled inductor winding... N 2 via diode D 1. Give capacitor C 1. Charging; simultaneously, input DC voltage.V in Output electrical energy to maintain the capacitor C 1 voltage V C1 and capacitor C 2 voltage V C2 Balance; output diode D 2. Reverse bias, output capacitor C 3. Load resistor R Independent power supply, the first switching mode ends; S2, Second switching mode: The power switching transistor... S 0 turn off, diode D 1. Reverse bias, DC voltage V in ,capacitance C 1. Coupled inductor winding N 3. Through the output diode D 2. Give the load R and output capacitor C 3. Power supply, DC voltage V in and capacitor C 1 is a capacitor C 2. Charging, when the current in the coupled inductor winding... i N1 This mode ends when it reaches its lowest point.

[0017] The beneficial effects of this invention are as follows: 1. This invention breaks through the bottleneck of traditional Boost converters being limited by series impedance and having difficulty in increasing voltage gain under high duty cycle. It can achieve a boost ratio much higher than that of traditional solutions within a reasonable duty cycle range, effectively adapting to the power conversion needs of low-voltage input and high-voltage output, such as photovoltaic power generation. 2. In this invention, compared with the discontinuous input current problem of Delta source converter, this invention can maintain continuous input current, significantly reduce input current ripple, reduce the impact on upstream photovoltaic modules, and at the same time reduce EMI filtering costs and system losses. 3. This invention overcomes the limitation of the duty cycle range of Delta source converters, allowing the converter to operate stably in a wider duty cycle range, improving the flexibility of the control scheme, and avoiding the switching losses and device stress problems caused by extreme duty cycles. 4. While achieving the same high gain, this invention effectively controls the voltage stress of power devices such as switching transistors, diodes, and capacitors, making them significantly lower than the output voltage. This allows for the use of devices with lower withstand voltage ratings, reducing system costs and improving the overall reliability of the circuit. Attached Figure Description

[0018] Figure 1 This is a low-cost improved coupled inductor Delta source DC-DC boost converter; Figure 2 The main waveform diagram of a low-cost improved coupled inductor Delta source DC-DC boost converter; Figure 3 Equivalent circuit diagram of the first switching mode of a low-cost improved coupled inductor Delta source DC-DC boost converter; Figure 4 Equivalent circuit diagram of the second switching mode of a low-cost improved coupled inductor Delta source DC-DC boost converter; Figure 5 This is a Simulink simulation waveform; Figure 6 This is another Simulink simulation waveform; Figure 7 This is another Simulink simulation waveform; Figure 8 This is another Simulink simulation waveform; Figure 9 This is another Simulink simulation waveform; Figure 10 This is another Simulink simulation waveform; Figure 11 This is another Simulink simulation waveform.

[0019] Explanation of the labels in the diagram: V in It is a DC voltage source. S 0 represents the power switching transistor. D 1 is the first auxiliary diode. C 1 is the first auxiliary boost capacitor. C 2 is the second auxiliary boost capacitor. D 2 is the output diode. C 3 is the output voltage regulator capacitor. R For load, N 1. N 2. N 3 represents the three windings of the coupled inductor, and the winding current of the coupled inductor is... i N1 The turns ratio of the coupled inductor is n 23 = N 2: N 3. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] like Figure 1-11 As shown in the figure, an embodiment of the present invention provides a low-cost improved coupled inductor Delta source DC-DC boost converter, including a DC voltage source. V in ,diode D 1. Diode D 2. Capacitor C 1. Capacitor C 2. Capacitor C 3. Load resistance R Power switching devices S 0 and the coupled inductor; the coupled inductor includes three windings and the winding current of the coupled inductor. i N1 The three windings are respectively windings N 1. Winding N 2 and winding N 3; The DC voltage source V in The positive terminals are respectively connected to the diode. D 1. Positive terminal, capacitor C 1. Cathode electrical connection; the diode D The cathodes of 1 are respectively connected to the coupled inductor windings N 1's positive terminal and coupled inductor winding N 2. Cathode electrical connection; the capacitor C The positive terminal of 1 is connected to the capacitor. C 2's positive terminal and coupled inductor winding N 2's positive terminal and coupled inductor winding N 3. Positive electrical connection; the coupled inductor winding N The cathodes of 1 are respectively connected to the coupled inductor windings N 3 Cathode, power switching devices S 0 drain, diode D 2 is electrically connected to the positive terminal; the diode D The cathodes of 2 are respectively connected to the output voltage regulator capacitor. C 3's positive terminal, load resistor R One end is electrically connected; the DC voltage source V in The cathodes are respectively connected to the capacitor C 2 Cathode, power switching device S 0 source, output voltage regulator capacitor C 3 Cathode, Load Resistor R The other end is electrically connected.

[0022] Specifically, the converter can achieve high voltage gain, common input and output ground, and continuous input current. The power switching device... S 0 represents a MOSFET switch, whose gate is used to receive a drive signal, enabling the switch to be turned on and off. The three windings of the coupled inductor... N 1. N 2. N 3. Adopts a common core structure, winding N 1 and winding N 2. Winding N Mutual inductive coupling exists between the capacitors 3 and 4, which is used to increase voltage gain and suppress current ripple. C 1 and capacitor C 2 are voltage divider capacitors; both have equal capacitance values, used to divide the input voltage, reducing the device's withstand voltage requirement and lowering the overall cost. The diode... D 1 and diode D Both are Schottky diodes, characterized by low on-state voltage drop and fast switching speed, used to reduce the conduction losses of the converter. The output voltage regulator capacitor... C 3 is an electrolytic capacitor used to stabilize the output voltage, suppress output voltage ripple, and ensure stable voltage across the load. The winding of the coupled inductor... N 1. N 2. N The turns ratio of 3 can be adjusted according to actual voltage gain requirements, with an adjustment range of 1:1:1 to 1:3:3. The power switching device... S The duty cycle of the converter is adjustable from 0.1 to 0.8, allowing for continuous adjustment of the output voltage. The converter has an input voltage range of 12V-48V and an output voltage range of 50V-200V, making it suitable for applications with low to medium voltage input and medium to high voltage output.

[0023] A low-cost control method for an improved coupled-inductor Delta-source DC-DC boost converter is disclosed. This method, applied to the aforementioned low-cost improved coupled-inductor Delta-source DC-DC boost converter, includes two switching modes: a first switching mode and a second switching mode, described in detail below. S1, First switching mode: Power switching device S 0 conduction, capacitor C 2. Through power switching devices S 0 for coupled inductor winding N 1. During charging, due to the principle of magnetic induction, the coupled inductor winding... N 2 via diode D 1. Give capacitor C1. Charging; simultaneously, input DC voltage. V in Output electrical energy to maintain the capacitor C 1 voltage V C1 and capacitor C 2 voltage V C2 Balance; output diode D 2. Reverse bias, output capacitor C 3. Load resistor R Independent power supply, the first switching mode ends; S2, Second switching mode: Power switching device S 0 shutdown, diode D 1. Reverse bias, DC voltage V in ,capacitance C 1. Coupled inductor winding N 3. Through the output diode D 2. Give the load R and output capacitor C 3. Power supply, DC voltage V in and capacitor C 1 is a capacitor C 2. Charging, when the current in the coupled inductor winding... i N1 This mode ends when it reaches its lowest point.

[0024] In this invention, a low-cost improvement is made to the control signal V of a coupled inductor Delta source DC-DC boost converter. gs Its control power switch S The switching on and off of the three-winding coupled inductor, and the winding current. i N1 , i N2 , i N3 ,diode D voltage of 1 V D1 ,diode D 2 voltage V D2 Power switch S 0 voltage V S0 The waveform is as follows Figure 2 As shown: Its working process is divided into two switching modes, namely the first switching mode and the second switching mode, which are described in detail below: The first switching mode corresponds to Figure 2 [ in] t 1, t 2]: Equivalent circuit, such as Figure 3 As shown, at this stage, the power switching transistor S 0 conduction, capacitor C 2. Through power switching devices S 0 for coupled inductor winding N 1. During charging, due to the principle of magnetic induction, the coupled inductor winding... N 2 via diode D 1. Give capacitor C 1. Charging; simultaneously, input DC voltage. V in Output electrical energy to maintain the capacitor C 1 voltage V C1 and capacitor C 2 voltage V C2 Balance; output diode D 2. Reverse bias, output capacitor C 3. Load resistor R Independent power supply, the first switching mode ends. The second switching mode corresponds to... Figure 2 [ in] t 2, t 3]: Equivalent circuit as Figure 4 As shown, power switching transistor S 0 shutdown, diode D 1. Reverse bias, DC voltage V in ,capacitance C 1. Coupled inductor winding N 3. Through the output diode D 2. Give the load R and output capacitor C 3. Power supply, DC voltage V in and capacitor C 1 is a capacitor C 2. Charging, when the current in the coupled inductor winding... i N1 This mode ends when the voltage drops to its lowest level. Based on the above analysis, the output voltage gain can be derived. G The expression is as follows: ;in d Power switching transistor S With a duty cycle of 0, its operating range is (0,1), and the turns ratio of the coupled inductor is... n 21 = N 2: N 1.

[0025] It should be noted that, as Figure 5 As shown, the input voltage Vin =40V, output voltage V out =300V, n 21 =4. Figure 5 The input voltage is 40V and the output capacitor voltage is approximately 300V. Figure 6 Power switch S The drive signal, voltage, and input current of 0, among which S The voltage is 166V and the input current amplitude is 27.4A. Figure 7 For capacitor C 1. Voltage approximately 142V and capacitor approximately C 2. Voltage 180V. Figure 8 diode D 1. Peak voltage approximately 237V and diode D 2. The peak voltage is approximately 298V. Figures 9-11 For coupled inductor windings N 1. Voltage and current N 2. Voltage and current N 3. Voltage and Current. As can be seen from the figure, the input current is continuous and has a high output gain, while the capacitor voltage is low, lower than the output voltage.

[0026] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A low-cost improved coupled inductor Delta source DC-DC boost converter, characterized in that, Including DC voltage sources V in ,diode D 1. Diode D 2. Capacitor C 1. Capacitor C 2. Capacitor C 3. Load resistance R Power switching devices S 0 and coupled inductance; The coupled inductor includes three windings and the winding current of the coupled inductor. i N1 The three windings are respectively windings N 1. Winding N 2 and winding N 3; The DC voltage source V in The positive terminals are respectively connected to the diode. D 1. Positive terminal, capacitor C 1. Cathode electrical connection; the diode D The cathodes of 1 are respectively connected to the coupled inductor windings N 1's positive terminal and coupled inductor winding N 2. Cathode electrical connection; the capacitor C The positive terminal of 1 is connected to the capacitor. C 2's positive terminal and coupled inductor winding N 2's positive terminal and coupled inductor winding N 3 is electrically connected to the positive terminal; The coupling inductor winding N The cathodes of 1 are respectively connected to the coupled inductor windings N 3 Cathode, power switching devices S 0 drain, diode D 2 is electrically connected to the positive terminal; the diode D The cathodes of 2 are respectively connected to the output voltage regulator capacitor. C 3's positive terminal, load resistor R One end is electrically connected; The DC voltage source V in The cathodes are respectively connected to the capacitor C 2 Cathode, power switching device S 0 source, output voltage regulator capacitor C 3 Cathode, Load Resistor R The other end is electrically connected.

2. The low-cost improved coupled inductor Delta source DC-DC boost converter according to claim 1, characterized in that, The converter can achieve high voltage gain, common ground for input and output, and continuous input current.

3. A low-cost improved coupled inductor Delta source DC-DC boost converter according to claim 2, characterized in that, The power switching device S 0 represents a MOSFET switch, whose gate is used to receive a drive signal to enable the switch to turn on and off.

4. A low-cost improved coupled inductor Delta source DC-DC boost converter according to claim 3, characterized in that, The three windings of the coupled inductor N 1. N 2. N 3. Adopts a common core structure, winding N 1 and winding N 2. Winding N Mutual inductance coupling exists between the three components, which is used to increase voltage gain and suppress current ripple.

5. A low-cost improved coupled inductor Delta source DC-DC boost converter according to claim 4, characterized in that, The capacitor C 1 and capacitor C 2 are voltage divider capacitors. The capacitance values ​​of the two capacitors are equal. They are used to divide the input voltage, reduce the voltage withstand requirements of the device, and reduce the overall cost.

6. A low-cost improved coupled inductor Delta source DC-DC boost converter according to claim 5, characterized in that, The diode D 1 and diode D Both are Schottky diodes, which have the characteristics of low forward voltage drop and fast switching speed, and are used to reduce the conduction loss of the converter.

7. A low-cost improved coupled inductor Delta source DC-DC boost converter according to claim 6, characterized in that, The output voltage regulator capacitor C 3 is an electrolytic capacitor used to stabilize the output voltage, suppress output voltage ripple, and ensure stable voltage across the load.

8. A low-cost improved coupled inductor Delta source DC-DC boost converter according to claim 7, characterized in that, The winding of the coupled inductor N 1. N 2. N The turns ratio of 3 can be adjusted according to the actual voltage gain requirements, and the adjustment range of the turns ratio is from 1:1:1 to 1:3:

3.

9. A low-cost improved coupled inductor Delta source DC-DC boost converter according to claim 8, characterized in that, The power switching device S The duty cycle of the converter is adjustable from 0.1 to 0.

8. The output voltage can be continuously adjusted by adjusting the duty cycle. The input voltage range of the converter is 12V-48V, and the output voltage range is 50V-200V, which is suitable for application scenarios with medium and low voltage input and medium and high voltage output.

10. A low-cost control method for an improved coupled-inductor Delta-source DC-DC boost converter, applied to the low-cost improved coupled-inductor Delta-source DC-DC boost converter described in claim 9, characterized in that, The low-cost improved control method for the coupled inductor Delta source DC-DC boost converter includes two switching modes: a first switching mode and a second switching mode, which are described in detail below. S1, First switching mode: Power switching device S 0 conduction, capacitor C 2. Through power switching devices S 0 for coupled inductor winding N 1. During charging, due to the principle of magnetic induction, the coupled inductor winding... N 2 via diode D 1. Give capacitor C 1. Charging; at the same time Input DC voltage V in Output electrical energy to maintain the capacitor C 1 voltage V C1 and capacitor C 2 voltage V C2 Balance; output diode D 2. Reverse bias, output capacitor C 3. Load resistor R Independent power supply, the first switching mode ends; S2, Second switching mode: Power switching device S 0 turn off, diode D 1. Reverse bias, DC voltage V in ,capacitance C 1. Coupled inductor winding N 3. Through the output diode D 2. Give the load R and output capacitor C 3. Power supply, DC voltage V in and capacitor C 1 is a capacitor C 2. Charging, when the current in the coupled inductor winding... i N1 This mode ends when it reaches its lowest point.

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